Crawler Transporter (Part 4)

The Crawler Transporter is too detailed for the intended use. I've gone on an extreme polygon diet and it still not enough. Currently, the 3D model for the Crawler Transporter stands at 87,386 polygons. I need it to be no more than 15,000, 17,500 absolute maximum, and there still more objects to add...

Here is the full 3D model so far.

[edit] Changed the title from Part 3 to 4, it's late and I'm watching The Bourne Legacy.